In this unit we are going to open a door into a fascinating world. The world of minerals. It tends to be apalling and attractive for students and teachers. Its target students are from a level o 1st ESO. Students are going to learn about minerals and its composition and inherent characteristics of minerals, properties, exploitation and usefulness. Moreover, we will see different methods of extraction with videos.
It will take three sessions to complete our unit although there are some extra materials for outstanding students.
You have
all the links in this unit organized and collected at this site:
Session 1
Presentation
with the video :
Then you
have the tapescript of the video to comment and make some questions.
Tapescript
(pdf):
Earth Materials
What do you think of when you
hear the phrase 'natural resource?' Many people think of something that comes
from Earth and that we as humans do not make ourselves. The Earth has many
natural resources, known as Earth materials. There are four main resources, and
they include minerals, rocks, soil and water. These four resources work
together to form and sustain the majority of life on Earth.
Although these four resources
are the most common, there are other Earth materials that are important and
unique. Let's examine two additional types of Earth materials, known as metals
and precious rocks.
Metals
First, let's examine
metals. Metal is a substance that frequently has a shiny
surface, conducts electricity and heat, and can be melted and shaped. If you
look around you, there is most likely metal somewhere in your view. Although we
mainly think of metal as a construction material or a component in electronics,
there is actually metal found naturally within the Earth. Metals are essential
nutrients that organisms need to grow and survive and are necessary to maintain
healthy ecosystems.
Most metals are extracted from
ores. Ores are naturally-occurring rocks that contain metals
and other minerals. A rock is considered an ore if it contains a large amount
of the metal and if that metal can be economically extracted from the rock.
Basically, there are many types of rocks that contain metals, but some only
contain small amounts, so it is not worth the expense of extracting the metal.
When extracting metals, people look for large concentrations of ores so that
they can make the largest profit for the extraction effort.
Humans extract metals from the
Earth for a variety of reasons. One of the most famous natural metals is gold.
During the Gold Rush, people traveled across the United States in hopes of
extracting gold from the land and becoming wealthy. Other natural metals
include aluminum, which is used to make cans, copper for wiring, lead for
batteries, silver for jewelry, and iron for steel.
Precious Rocks
Now, let's examine precious
rocks. What does the word 'precious' mean to you? Although most of us do not
describe rocks as precious, some rocks are. Precious rocks are
stones that are very rare and have economic value. Precious rocks are also
referred to as 'gemstones' or 'jewels.' These stones gain their economic value
due to their aesthetics, or natural beauty. They are also very durable and
difficult to break or scratch. Precious rocks are commonly used in jewelry but
are also carved or inserted into artwork or furniture.
Precious rocks come in many
different colors, shapes and compositions. These stones also formed in a
variety of manners. Most precious rocks are formed when a rock is exposed to a
change in temperature, pressure or interacts with another solution. Some stones
are even formed within the molten magma of volcanoes!
We have time to introduce
vocabulary of the unit and comment on some doubts they may have about the
readiing.at the same time, we make a presentation of the unit.
Make questions to check their understanding.Introduce new vocabulary.
Promote a debate about the importance of minerals.
To introduce the next session:
In this video they see the properties of minerals.
Session 2
1. Characteristics of minerals
Write them down in you notebook.
2. Types of minerals
Make a chart with bubbles .
We have further materials to widen :
http://www.kidsloverocks.com/html/crystals.html about
crystals.
Session
3
Extraction and processing
About minig process.
Tapescript we provide as a
pdf:
Extracting Surface Minerals
Surface mining is just what it sounds like - removing minerals that
are near the earth's surface because this is where the ore deposits are
located. When the ore deposits are very large, open-pit mining is utilized. A large, open pit is
created as machines scrape off any earth that is not ore and set it to the
side. This material is called overburden,
and as the overburden is scraped off, it's piled into spoil banks.
After the overburden is cleared from the ore,
explosives are used to break up the ore material that is being removed from the
ground, which is then taken away to be refined. The size of the ore bed
increases as mining continues, and eventually, the pit becomes a very large
bowl-shaped hole in the earth's surface. When the ore is found in a wide area
but it's not very deep in the ground, strip mining is used.
In strip
mining, instead of creating one large pit in the ground, long narrow strips
are dug out. The overburden is removed and piled up along the strip. Once the
ore is removed, the overburden is dumped back into the strip. While this may
sound like a good method because the holes are re-filled instead of left open,
the land actually looks more like a washboard after strip mining because of all
of the re-piled soil.
Extracting Minerals Deep Underground
Some minerals are found very deep below Earth's
surface - sometimes hundreds or thousands of feet deep! To remove these
minerals from the ground, subsurface
mining is used. In subsurface
mining, a long tunnel is created either horizontally or vertically. The tunnel
walls are reinforced with wood and ventilation shafts are created to provide
air to the miners underground. The minerals themselves are removed a number of
different ways.
One way is to blast apart the material and then send
the ore pieces up to the surface in carts. Another method is longwall mining, which is when
coal is sheared from the wall and collected on a conveyor belt, much like a
potato peeler shears away layers of a potato. This is a very efficient way of
extracting coal from an underground mine. Another method is solution mining, which is when
hot water is injected into the ore to dissolve it. Once the ore is dissolved, air
is pumped into it, and it's bubbled up to the surface.
The Harmful Effects Of Mining
While mining provides us with the minerals we need, it
is also very destructive because it disrupts the landscape both on the surface
and underground. It also causes quite a bit of pollution and can harm or kill
mine workers. Surface mining is destructive to landscapes because it can cause
changes in the topography and drainage and strips the land of vegetation, soil
and rocks. The spoil banks of surface mining erode and weather away, and
rainfall leaches toxic chemicals into the earth. In some cases, entire
mountaintops have been removed for surface mining!
Further materials to deepen for outstanding students:
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